Locking screw and the like



Patented Mar. 9, 1926.

UNITED sTaTEs4 ARCHIBALD STANNARD CUBITT, OF LONDON, ENGLAND.

LOCKING SCREW AND THE LIKE.

illmilicaton led May 13, 1925. Serial No. 30,097.

To all 'whom t may concern:

Be it known that I, ARCHIBALDy STANNAnD CUBITT, a subject of the King ofGreat Britain, residing at London, England, have 1nvented certain newand useful Improvements in and Relating to Locking Screws and 'the like,of which the following is a specification.

Thepresent invention relates to improvements in and relating to lockingscrews and the like, and aims to provide a screw-threaded member whichislockable in a screwthreaded hole by a locking action brought about bythe means on the member itself.

In a constructional form under the present invention a screw-threadedmember comprises two like or similar screw-threaded portions, as regardsexternal diameter and screw thread, united by a screw-1n union ofdifferent pitch to form normally yone continuous screw-threaded memberwhich is v lockable in a screw-threaded hole by a relative movement ofthe portions tending to 'unscrew these from each other.

may have the external diameter of one or the leading portion of thescrew made slightly smaller than the other or main por,-` tion.

One of, or both of the junction faces may be raked back or cambered.

The leading portion may be provided with means for holding or rotatingit with the aid of a tool.

The accompanying drawings show practical forms of carrying the inventioninto elfect.

In the drawings, Fig. l is a view of a bolt or `stud in normal position,Fig. 2 is a view with the components separated, Fig. 3 shows the bolt orstud in a locked position in its work, Fig. 4 is a form of screw-nuttedbolt attached to its work, Fig. 5 shows a spherical ended bolt, Fig. 6 aconcave ended bolt, and Fig. 7 a conical ended bolt.

Referring to the constructional example of a machine screw depicted byFigs. 1 to 3 ofthe drawings the end portion a of an ordinary machinescrew b is turned down to a This compound screw b, d can now be easilyscrewed into a hole f suitably threaded but on attempting to withdraw itthe main portion Z2 attempts to unscrew from the collar or lockingportioncl `and the screw-in union being of a different pitch to the mainscrew etfectually locks the combination. y l A In the construction shownin Fig. 4 provision may be made for imparting a relative movement to theportions tending so as to definitely lock the screw, or the like in itshole, or to 'lock a nut .or the like thereon.

Thus the collar d at its outer end may be notched as at L orcross-passaged for turning by a screwdriver, tommy or the like, orexternally or internally machined square, hexagonal, or octagonal, orotherwise appro# priately provided with means for co-acting with aSpanner, coach-key, or the like, or other tool. i

Thus, for example, a nut k1I may be screwed up tight to a face of thework, and then the collar portion l may be., turned the reverse hand tomove this relatively to the main portion b to lock the nut The nutconven-y iently has the same engagement with the bolt as an ordinarynut, with the addition of, say, two threads to engage the collarportion.

According to the present invention also, the external diameter of thecollar portion d may be made slightly smaller than the main portion;this in general, but particularly in the ycase of a machine screw, studor thel like, so that when the compound screw b, d is screwed into asuitablythreaded hole, the collar portion d shall advance without suchfrictional resistance as to cause it to be screwed so tightly on thescrewthreaded shouldered down part a ofthe main screw b as to preventthe main screw b fromafterwards attempting to unscrew from the collarportion d when attempt is made to withdraw the main screw.

Or otherwise such reduction of diameter may be employed to facilitaterelative movement of the portions tending to unscrevv these from eachother.

As facilitating the screw b attempting to unscrew from the collarportion d, or :facilitating relative movement of the portions tending tounscrew these from each other, the junction faces, or one of these,

may be raked back or cambered, as indi-cated by dotted outline at j, sokas to reduce the Contact diameter and thus reduce the friction tendingto lock the parts together.

The difference of pitch' between the main screw and the lesser pitchscrew union isa measure or determining factor of their relative angularmovement required to look. In an example which gives good results theexternal' portion or main screw is threaded at the blind end, thecorresponding .end of th'ecollar tendsv to jfam in the bottom of thehole, thisamming facilitating the relative angular move-nient of theparts tale ing place when attempt is made to withdraw the screw or stud.

What I claim is l. A locking screw comprising in, combination, a mainpart, an external thread thereon, a shouldered down end, an exten nalthread thereon of like hand but different pitch to said external threadon the main part, a collar part, an external thread thereon of like handand pitch to the external thread on said main part, and anl internalthread in said collar for engaging the external thread on saidshouldered down end, the main part andthe collar part when united thecollar part tending to unscrew these from each other.

2. A locking screw comprising in combination, a main part having acambered face, an external thread on said main part, a

shouldered down end, an external threadv thereon of like hand butdifferent pitch to said external thread on the main part, a

Collar part,`an external thread thereon of like hand and pitch to theexternal thread on sail main part, and an internal thread in sai-dcollar for engaging the external thread on said shouldered down end, themain part and the collar part when united forming one continuous screwthreaded bolt of like hand and pitch capable of being locked in ascrewthreaded hole by a relative movement between the main part and thecollar part tending to unscrew these fronreach other.

3. A locking screw comprising in combination, a main part, an externalthread thereon, a shouldered down end, an external thread thereon oflike hand Abut different pitch to said external thread on lthe mainpart, a collar'part, an external thread thereon of like 'hand and pitchto the external thread on said main part, and an internal thread in',said collar for engaging the external thread on said shouldered downend,

c the main i part and the collar part Whe-n united forming onecontinuous screw threaded boltof ylike hand and pitch capable of beinglocked in a screw-threaded hole by a relative movement between the mainpart and the collar part tending to unscrew these from each other, andmeans on said collar for engaging an actuating tool.

ln testimony whereof, I aflix my signature.

ARCHIBALD s'raNNAnD CUBITT;

